1. Field of the Invention
The present invention relates to a surgical retractor which comprises an inflatable sleeve that may be deflated, when not in use, so as to assume a precoiled position; and which may be inflated by air pressure, when in use, so as to assume an uncoiled state in which it defines a generally circular aperture.
2. The Prior Art
Surgical retractors are used for spreading apart or separating the walls of natural body orifices or for spreading the margins of surgical incisions. With the edges of an incision spread apart, the surgeon has access to the underlying tissues or organs permitting a clear view of the surgical site and access for a desired surgical or medical treatment. Thus, for example, an abdominal retractor may be used in an abdominal incision to hold back the skin, subcutaneous fat and the internal peritoneal wall for ready access to the many abdominal organs.
Examples of prior art surgical retractors and related medical devices are as follows.
U.S. Pat. No. 2,812,758 discloses a circular surgical retractor which can be expanded or contracted, apparently by hand, and then locked in position for producing a desired circular opening in the abdominal cavity.
U.S. Pat. Nos. 4,459,978 and 4,585,000 disclose expandable medical devices having fingers which can expand upon the retraction of a hub portion by the activation of a flexible shaft.
U.S. Pat. No. 3,807,393 discloses an expandable surgical retractor which again can be locked in expanded position after being manually extended.
U.S. Pat. No. 4,334,652 shows a circular expandable device which is, when contracted, used to clamp surgical bodies.
Each of these prior art devices have certain disadvantages. For example, during the retraction, or the clamping, it is difficult to observe or to reach the exposed anatomical structures. In addition, there is stressing and traumatizing of the tissue being retracted. These prior art problems are the result of having to hastily expand or contract the surgical retractor, whereby the forces being applied to the device and to the patient are not uniformly or smoothly employed, and the effect is to traumatize the tissue adjacent to the device. A further cause of tissue trauma/stress is the fact that direct, sustained contact between an unyielding retractor surface (a metal band, rim, fork or blade) and retracted tissue occurs. Another disadvantage is that a nurse or surgical attendant is required to be present for extended periods of time in order to manually maintain the retractor in position during a lengthy surgery.